In recent years, the size of wind turbines has increased significantly which has resulted in still larger, heavier and more complex wind turbine components. Especially, components of the nacelle together with the wind turbine rotor have increased both in size, weight and complexity. In order to meet the increased size and weight of the nacelle components, as well as the increased size of the rotor, the nacelle has also increased in size and weight.
The increased size and complexity of different components in the wind turbines, such as the nacelle and the wind turbine rotor, have resulted in production at large and specialized production plants. The plants are often positioned in a rather few central locations around the world and thus relying on transporting many of the different components in wind turbines over long distances to the places of erection. The transportation of wind turbine components may primarily involve trains or ships. Further, the transportation may include large trucks and combinations of trains, ships and trucks.
The transportation of the nacelle of a wind turbine over long distances involves problems as the nacelle includes a number of components with rotating means. The components include not only the gear, but also the one or more generators which all have shafts rotating during normal use of the wind turbine in a number of bearings and engaging with toothed wheels of the gear. During the long transportation, the protective oil films that separate the rotating means from the bearing and toothed wheels from each other may be ruptured or vanish due to vibrations and the weight of the shafts, resulting in damage to the shafts, the bearings or the toothed wheels. Continuos low frequency vibrations, such as vibrations from a ship engine, may be especially harmful to the components in question.
The damage is often quite small in size, e.g., less than 1/1000 millimeter, and thus not be visible to the human eye but may nevertheless result in a reduced lifespan for the components.
In order to avoid the problem, the rotating means may be equipped with transportation furnishings at the shaft ends. The furnishings allow the shafts to be held in a position in which the weight is not transferred to the bearings. The furnishings are however less useful in connection with the gear and especially the toothed wheels due to the structural nature of the gear.
Further, furnishings are difficult and time consuming to position correctly in a nacelle before the transportation starts.
An object of the invention is to establish methods and system for wind turbines without the above-mentioned disadvantage and especially without the rupturing or vanishing of the oil film in rotating means of a wind turbine such as gears and generators.
A further object of the invention is to establish control systems for monitoring and optimizing the established methods and system for wind turbines.